Computer systems, servers, workstations, and other communication, computational, and control devices housed in cabinets, closets, and various other enclosures have developed into highly complex and highly populated electronic systems. As the complexity of these systems has increased, power and heat dissipation requirements have become more burdensome. Typical techniques for dissipating heat include usage of fans, ducting, and/or passive heat sinks.
An appropriately designed system supplies adequate cooling to maintain component die temperatures within thermal specifications. Various cooling techniques involve supply of a low local-ambient temperature, assuring an adequate airflow, and reducing die to local-ambient thermal resistance. When component die temperature is kept within suitable limits, chipset reliability, performance, and functionality can be maintained. Operation at temperatures outside the specifications can degrade system performance and may permanently change component operating characteristics.
Simple and effective system cooling is generally sought through careful design and placement of fans, vents, and ducts. If additional cooling is required, thermal design techniques may be supplemented by usage of component thermal devices. Fan and heat sink sizes can be selected to accommodate considerations including size, space, and acoustic noise constraints. In one example, a heat sink can be attached to a heat-generating component, such as a processor, using a strap clip. In another example, a reference beat sink can be attached to a component via thermal adhesive tape.
Computing, communication, control, and other systems that have a hot-plug or hot-swap capability create additional difficulties in maintaining a sufficiently cool internal temperature. For example, a system that includes one or more Peripheral Component Interconnect (PCI) buses generally supports hot-plug and hot-swap capabilities that allow removal and installation of PCI cards while the system remains running. Hot-pluggable components may include disk drives, PCI cards, fan trays, power supplies, and other components. One difficulty with hot-pluggable and hot-swappable components is that circuits and interconnects on different cards or boards may collide or touch during physical manipulation, possibly resulting in short-circuiting, physical damage, and/or electrical damage. To avoid touching or collisions between boards or cards during manipulation, a system generally may include one or more dividers that separate the cards, boards, or components and prevent physical contact and resulting damage. Unfortunately, the dividers obstruct air flow within a system, thereby interfering with cooling. The problem is accentuated by the market preference for smaller, more compact systems with more compact card configurations and fans arranged in close proximity to the cards.